The present invention relates to data center infrastructure, and more particularly, this invention relates to extending link aggregation to multiple switches without restriction to vendor or number.
Network packet switches use Link Aggregation (LAG) to create a higher bandwidth port channel using multiple switch ports. LAG may be formed statically or dynamically. Static LAG has a fixed number of ports which are always members of the LAG if they are configured to be members of the LAG. Dynamic LAG, according to Link Aggregation and Control Protocol/LACP IEEE 802.3AD, provides facilities where port members may dynamically join and leave the dynamic LAG. Distributing or load balancing network traffic over the LAG ports is accomplished with algorithms, various different algorithms being currently available to control distribution across members in a LAG. Good algorithms provide efficient ways of hashing packets over the member ports, make sure each port is used equally, and ensure that no one port gets congested.
A switching processor, such as a switching application specific integrated circuit (ASIC) may be used to provide various algorithms which choose ports for network packets. Most of the algorithms are based upon tuples formed from information in the packet header of the packets. The tuples typically include a source media access control (MAC) address, a destination MAC address, a virtual local area network (VLAN) identifier, a source internet protocol (IP) address, a destination IP address, a source transport port, and a destination transport port. Some algorithms consider additional programmable factors to achieve better distribution of ports and/or other usage metrics.
Server to switch LAG is often used to achieve a high bandwidth pipe that is not prone to single link failures. This is also often done across multiple cooperating switches to protect against switch failures. However, conventionally, this requires the switches to be from the same vendor, and moreover, many times the switches need to be the same model. Often, LAG is also limited to only a pair of switches.
LAGs are important properties of the switches in a network and impact the performance of the switches and network in general. LAGs also alter the overall performance of the set of switches connected together. Accordingly, it would be beneficial to allow multiple switches to be connected together in a LAG to a server and to allow switches from multiple vendors and multiple model numbers to be grouped together in a LAG.